Method of dry cleaning



March 7, 1939- A. E. HATFIELD METHOD OF" DRY CLEANING Filed March l,1937 .EE LS?,

ATTORN Y Patented `lifar. 7', T939 NETE@ STATES PAT@ 'ortica CanadApplication March 1, 1937, Serial No. 128,462

6 Glams.

My invention relates to a method of dry cleaning, that is, a process ofcleaning garments, fabrics, textiles, and the like, by means of solventssuch as light hydrocarbons, including gasoline and naphtha, andchlorinated hydrocarbons such as carbon tetrachloride ortrichlorethylene and like organic solvents.

'I'his application is a continuation in part of my copendingapplication, Serial No. 35,832, filed U August 12, 1935, now Patent2,072,332, dated March 2, 1937.

In my Patent 1,990,691, dated February 12, 1935, I disclosed a processof dry cleaning which enabled both greasy soils and water soluble soilsl5 to be removed without the dangers and disadvantages attending thehumidifying of a dry cleaning solution. In the process of my patent, Iam able to accomplish the results by first rendering the fabrics waterrepellent and then subsequently humidifying the dry cleaning solution,

In practical operation, a dry cleaning bath is used for successivebatches of clothes. After the dry cleaning solvent has been oncehumidified, I have found that colloidal water is dispersed throughoutthe solution. This water is of such` small quantity that it is notobjectionable in causing clothes to shrink. I have found, however, thatthe presence of water has a deleterious effect when greasy soils areremoved. If it is attempted to remove greasy soils in the presence ofwater, upon the clothes being immersed in the cleaning bath, the dirt isfirst released- :from the clothes and then is redispersed because of thepresence of water and redeposited upon the clothes. This results inmaking the clothes look hazy and dull. In order to get perfect drycleaning, therefore, it is essential that the greasy soils be removedfrom the clothes and the dry cleaning solution clarified or filtered ofthe greasy dirt by filtration or the like, before it is attempted toremove the water' soluble soils by humidifying the dry cleaningsolution.

One object of my invention is to provide an imf proved method of drycleaning inwhich the greasy soils and Water soluble soils are removed instages. 'le

Another object of my invention is to provide a process of dry cleaningin which both greasy soils and Water soluble soils are removed from thefabrics without the danger of redeposition of soil upon the clothes.

Another object of my invention is to provide a process of dry cleaningin which a dry cleaning bath is alternately humidied andrendered sub-(ci. 8 142) d stantially anhydrous, and the same bath continuously usedfor cleaning successive batches of fabrics.

Other and further objects of my invention will appear from the followingdescription.

In the accompanying drawing, which forms part of the instantspecification and is to be read in conjunction therewith:

Fig, 1 is a schematic view showing the arrangement of the Washer, pumpand filter through lwhich cyclic ow of the solvent occurs.

Fig. 2 is a 'chart showing the stages of my process in outline.

In general, my invention contemplates the dehydrating of the drycleaning bath by means of a dehydrating agent after the water solublesoil has been removed by humidifying the dry cleaning bath in order thatthe same bath may be used for cleaning a subsequent batch of fabrics ofgreasy soil in the absence of water or moisture.

More particularly, I employ as a dehydrating agent a natural, hydroussilicate of alumina, known generally as bentonite which has the propertyof absorbing from ten to twenty-five times its weight of water.

Bentonite may be represented by the formula,

In the above formula, may represent any number from 1 to 15, dependingupon the dryness of the sample. The amount of chemically combined water,however, does not ordinarily exceed 2H2O. Bentonite, however, has verylittle chemical affinity for water. It is no more hygroscopic than anyinert, powdered, argillaoeous material. Bentonite, however, does nothave a great physical avidity for water in liquid form. In the formulagiven above, the alumina may be replaced to a considerable extent byiron, lime or magnesia and, to a very limited extent, by alkali.

More particularly, I may employ as a dry vcleaning solvent .any of thewell known agents such as naphtha, gasoline, carbon tetrachloride,trichlorethylene, and the like. The system is first filled with drycleaning fluid. The pump is started and dry cleaning uid is circulatedfrom the washer to the pump, through the filter and back to the washer.Filter aid, `which may be fuller's earth, diatomaceous earth, or thelike, is introduced into the circulating ring of the num. It isunderstood that the filter aid may be introduced at any suitablepointinto the ring.' A convenient place for its introduction is into thewasher. The filter aid is caught upon the leaves of the filter,pre-coats the filter and precludes 4its becoming clogged readily. Theamount of finely divided 4bentonite is then introduced, together withsome additional filter aid. Bentonite may be used alone, if desired.Instead of bentonite, I may employ other dehydrating agents, such ascalcium chloride and the like, either alone or with bentonite. However,when the dry cleaning fluid contains considerable moisture, thebentonite alone, in absorbing water from the dry cleaning fluid, maytend to clog the filter. 'I'he addition of bentonite along with adiatomaceous earth which is highly porous will assure that resistance toflow Will not build up unduly. The circulation is continued to permitany Water which might be present to be taken out of the dry cleaning uidby -the bentonite which is caught upon the leaves of the filter.

In my Patent 2,072,332, I disclose the dehydration of a dry cleaningbath in which` bath is dissolved a material capable of rendering thefabrics water repellant. In the instant case, the use of this additionagent is not contemplated and.

the process relates to a continuous use of a single bath which ischarged with moisture for the cleaning of successive batches of clothes.Moisture may be disseminated through a dry cleaning bath either by achemical dispersing agent, such as an absorbefacient or the like, or bymeans of mechanical dispersing devices such as viscolizers,homogenizers, or the like. Usually the moisture dispersed in less thanthe moisture tolerance of the fabric, that is not more than can beabsorbed by the fabric without injury to the same, it being contemplatedthat the moisture charged will be removed from the bath by the fabricsbeing cleaned. I have found, however, in practice, that the fabrics donot completely absorb the moisture from the bath. The amount of mois#-ture remaining in the vbath is an unknown quantity so that, when thebath is again recharged with moisture for the cleaning of a succeedingbatch of fabrics, it frequently happens that the quantity of moisture istoo great, resulting in injuryv to the fabrics. In other words, I haveobserved that there is a building up of moisture, due to the fact thatincreasingly greater quantities will remain when the bath -is repeatedlycharged with moisture, until such quantity is .present that injury isoccasioned.

In order to obviate the danger of charging a bath with excessivemoisture, I propose to dehydrate the bath before any moisture is chargedand before the fabrics are introduced into the dry cleaning bath. Inthis manner, I am enabled always to control the moisture which is addedWithout the necessity of determining the quantity of Water remaining inthe bath before adding additional moisture. Furthermore, by

substantially dehydrating a bath before charging a fresh bath ofclothes, the danger of redepositing the soil upon clothes, due to thepresence of water and thus obtaining dull or hazy work, is greatlylessened.

It will be understood that certain features and sub-combinations are ofutility and may be em-` ployed without reference to other features andsub-combinations. Ihis is contemplated by and is within the scope of myclaims. It is further obvious that various changes may be made indetails within the scope of my claims Without departing from the spiritof my invention. It is, therefore, to be understood that my invention isnot to be limited to the specic details shown and described.

Having thus described my invention, what I claim is:

l. In a process of dry cleaning in which a dry cleaning bath issuccessively humidii'ied prior to successive cleaning operations onsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging step.

2. In a process of dry cleaning in which a dry cleaning bath issuccessively humidied prior to successive cleaning operations onsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging step by contacting the bath withbentonite.

3. In a process of dry cleaning in which a dry cleaning bath issuccessively humidiiied prior to successive cleaning operations onsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging step by contacting the bath withbentonite and a lter aid.

4. In a process of dry cleaning in which a dry cleaning bath issuccessively humidied prior to successive cleaning operations onsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging step by contacting the bath with calciumchloride and bentonite.

5. In a process `of dry cleaning in which a dry cleaning bath issuccessively humidified prior to' successive lcleaning operations onsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging step by contacting the bath with calciumchloride and a filter aid.

6. In a process of dry cleaning in which a dry cleaning bath issuccessively humidified prior to successive cleaning operations orrsuccessive batches of fabrics, the steps of dehydrating the solventprior to each moisture charging stepby contacting the `bath withdiatomaceous earth and a dehydrating agent,

ARTHUR EDWARD HATFIELD.

